Building walls with fluid ducts that act as thermal barriers are known. For example, German OLS DE 298 04 095, entitled “Low-energy House,” discloses a building wall with a core zone that features fluid lines. In such walls that are equipped with a temperature barrier, it is possible to feed in low-temperature energy such as geothermal heat for air-conditioning purposes. Consequently, temperatures below 18° C., particularly geothermal heat in the form of solar energy, can also be used for air-conditioning purposes.